Endpoint and registry configuration

[mirceanis]

What's here

This changeset allows devs to configure the RPC endpoint and eventual registries they want to use.
This is useful for private nets and for properly configuring an infura project.
Any configuration should be done during app startup / sdk initialization.

There is a Networks registry that already has some defaults for the more popular public eth networks. Those can be overridden like so:

Networks.registerNetwork(Networks.mainnet.copy(rpcUrl = "http://127.0.0.1:8485"))

This will make the SDK try to use a localhost node to interact with the network.

Here's an example config for a private network:

val myNet = EthNetwork(
                name = "mynet",
                networkId = "0x6123",
                rpcUrl = "https://127.0.0.1:8545",
                //assuming this was deployed already to the private net
                ethrDidRegistry = "0x7efdca03e98e0dc2b855be647c39abe98421bfcf",
)
Networks.registerNetwork(myNet)
Uport.initialize(Configuration.setEthNetwork(myNet))

Networks can also be specified more granularly for individual classes but should only be used in isolation (see note below).
JWTTools accepts a preferredNetwork param
Configuration allows an ethNetwork to be set
EthrDIDResolver accepts a rpcUrl and a registry

Note

Throughout the codebase there is an assumption that the networks are configured at the start. Later changes to configuration will override the existing entries.